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Creators/Authors contains: "Bergner, John"

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  1. ; ; ; ; ; ; ; ; (, Chemical Communications)
    The chemical reduction of a π-expanded COT derivative, octaphenyltetrabenzocyclooctatetraene (1), with lithium or sodium metals in the presence of secondary ligands affords a new doubly-reduced product (1 TR 2− ). The X-ray diffraction study revealed a reductive core rearrangement accompanied by the formation of a single C–C bond and severe twist of the central tetraphenylene core. The reversibility of two-electron reduction and core transformation is further confirmed by NMR spectroscopy and DFT calculations. 
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  2. ; ; ; ; ; ; ; ; (, Journal of the American Chemical Society)
  3. ; ; ; ; ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract The chemical reduction of a π‐expanded polycyclic framework comprising a cyclooctatetraene moiety, octaphenyltetrabenzocyclooctatetraene, with lithium metal readily affords the corresponding tetra‐anion instead of the expected aromatic dianion. As revealed by X‐ray crystallography, the highly contorted tetra‐anion is stabilized by coordination of two internally bound Li+, while two external cations remain solvent separated. The variable‐temperature7Li NMR spectra in THF confirm the presence of three types of Li+ions and clearly differentiate internal binding, consistent with the crystal structure. Density‐functional theory calculations suggest that the formation of the highly charged tetra‐reduced carbanion is stabilized through Li+coordination under the applied experimental conditions. 
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